Project Summary/Abstract New World Health Organization guidelines recommend that all persons diagnosed with HIV receive partner notification services (PNS) and the President?s Emergency Program for AIDS Relief (PEPFAR) now requires all PEPFAR supported countries to implement PNS programs. How to implement PNS and whether PNS programs will prove safe and effective as they go to scale is uncertain. The University of Washington International Training and Education Center for Health (I-TECH) has worked with the Mozambican Ministry of Health and PEPFAR since 2016 to implement PNS programs in 29 clinics in Mozambique, providing PNS to over 16,000 persons newly diagnosed with HIV infection. The team implemented PNS using two models, a high-intensity support model that included new, dedicated PNS staff and supervisors in 3 facilities, and a low intensity support model that provided training and quarterly supervision to existing staff in 26 sites. This application proposes secondary analyses of data collected through PNS scale-up in Mozambique. Specific aim 1 will assess the reach and effectiveness of PNS programs in 29 clinics in Mozambique, comparing outcomes in high and low intensity clinics. Analyses will assess the proportion of persons diagnosed with HIV who received PNS (reach) and will evaluate conventional PNS indices related to partner notification, testing and HIV case-finding. Aim 2 will assess the impact of PNS on the total number of HIV cases identified in 29 clinics in Mozambique, an approach that will overcome many of the biases inherent in more traditional PNS evaluations. This aim will include a stepped-wedge analysis to assess the impact of PNS program implementation on the total number of HIV cases identified in each clinic, comparing high and low-intensity clinics and evaluating reach as a mediator of PNS effectiveness. Finally, aim 3 will evaluate how often disclosure of HIV status to a sex partner was associated with intimate partner violence or loss of financial support from a partner, and will identify factors associated with these adverse outcomes. The results of the proposed analyses will inform how PNS programs are implemented and evaluated in Mozambique and elsewhere around the world.